What is the mass of one mole of magnesium nitrate #Mg(NO_3)_2#?

2 Answers
Jan 2, 2016

Answer:

Got me! I know that 1 mole of magnesium has a mass of 24.3 g.

Explanation:

And I know that 1 mole of nitrogen has a mass of 14.01 g, and that 1 mole of oxygen has a mass of 15.99 g. Do you think that by adding the masses together, appropriately weighted, i.e. #1xxMg + 2xxN + 6xxO#, you would arrive at the formula mass of #Mg(NO_3)_2#?

After you do that, you could see if your summation is right. Good luck.

Jan 2, 2016

Answer:

It is equal to the molecular weight, 147 grams. Use the mole definition.

Explanation:

Mole is defined as:

#n=m/(Mr)#

where:

#m# is the mass in grams.
#Mr# is the molecular weight of the substance.

The molecular weight of a substance is equal to the sum of the molecular weights of the atoms that constitute it. For these atoms:

#Mg:24.3#
#N:14#
#O:16#

So the molecular weight:

#Mg(NO_3)_2=MgN_2O_6#
#Mr=23+2*14+6*16#
#Mr=147#

Therefore:

#n=m/(Mr)#

#m=n*Mr=1*147=147grams#